7.4L - Mil On With DTC P0446 Set - Reprogram Pcm (00-06-04-042)

7.4L - MIL ON WITH DTC P0446 SET - REPROGRAM PCM

TECHNICAL SERVICE BULLETIN

MALFUNCTION INDICATOR LAMP (MIL) ON WITH DTC P0446 CODE SET (REPROGRAM PCM)

Model(s): 1998-2000 Chevrolet and GMC C/K Models with 7.4 L Engine (VIN J - RPO L29) and California Emissions (NB6)

Section: 06 - Engine/Propulsion System

Bulletin No.: 00-06-04-042

Date: October, 2000

CONDITION

Some customers may comment on a Malfunction Indicator Lamp (MIL) that is illuminated. Further investigation will find a DTC P0446 code has been set.

CAUSE

The code is more likely to occur with less than 1/2 tank of fuel. The VCM monitors the performance of the EVAP system by applying a predetermined level of vacuum to the EVAP system. The VCM then monitors the vacuum decay rate. The VCM sets this DTC if the vacuum decay rate is greater than a predetermined value. The decay rate at idle is higher than the monitoring portion of the current calibration range will allow.

CORRECTION

Once the vent solenoid is verified to be operational, reprogram the vehicle with a new calibration.

PARTS INFORMATION

The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting on the TIS 2000 CD 13 shipped to dealers 7/6/00.

PARTS INFORMATION

Model Year	Original Production Calibration Part Number	New Service Calibration Part Number
1998	16250416	9388662
1998	16250419	9388663
1999	9351030	9338664
1999	9351033	9388665
2000	16259196	9388666
2000	16259199	9388667

WARRANTY INFORMATION

For vehicles repaired under warranty, use:

Labor Operation	Description	Labor Time
J6355	Prom - Reprogramming On Car	Use Published Labor Time